Add wrappers for malloc, calloc, realloc that check for out of memory

situations.  Use them in most places where malloc, and friends are used.
This results in clean error messages in an out of memory situation instead of
segfaulting or silently malfunctioning. In some places, it just allows to
remove some logging code.

PR 51568, PR 51569, PR 51571.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1172686 13f79535-47bb-0310-9956-ffa450edef68